Interactions between A1Σu+and b3Πustates of Na2

Following excitation to the B(1) 3 Pi u // state of Na 2 by the 4880 and 4965 AA lines of an argon-ion laser, the collision-induced system (2) 1 Sigma g + -A(1) 1 Sigma u + was recorded at high resolution by Fourier-transform spectrometry. The A(1) 1 Sigma u + approximately b(1) 3 Pi u interactions were studied in detail. The electronic part of the interaction matrix element ( 3 Pi 0,u mod H so mod 1 Sigma u + ) is independent of nu (b 3 Pi ) for the Li Li et al. (1984) numbering and is found to be 5.91+or-0.14 cm -1 .